Try that with battery by itself. See if you can reproduce that issue. Then remove the battery and use AC power alone. See if you can reproduce this issue. If it happens on one or the other, replace the offending item. If it happens on both, send the notebook in for service with AC and battery. (Most likely it is internal!)

Remember, you must test with just AC alone and battery alone in order to eliminate the possibility of an easy fix vs. serious repairs.

I would try riviera74s advise....yes it it safe to remove the battery from the laptop and run it with the battery removed and using the the power adapter.

Cleaning the fans and such is a good idea if you do not do it every once in a while, just when you are using compressed air be from a air compressor or canned air do it with the battery out. Also do not use the air and make your fans spin to as fast as you can it can kill a fan and yes using high pressure air can make then blow past 10k rpms......not a good thing. that goes for any fan you are blowing out. I use a toothpick or something to hold a fan so it cannot free spin. I killed a graphics card fan on a older video card seeing how fast i could make it spin...stupid:)